<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
  <script>
    function content(){
    // alert("我是三秒钟之后显示的内容")
      document.getElementById("p").innerHTML="我是三秒后显示的内容!"
    }
    setTimeout("content()",3000)
  </script>
</head>
<body>
<p id="content"> 请等三秒钟!</p>
<p id="p"> </p>
</body>
<style>
  #p{
    color:red;
  }
</style>
</html>
